This invention relates to lenses and reflectors for electric lights such as flashlights, spotlights, vehicle driving lights, fog lights and lighthouse lights. In particular, it relates to a method of concentrating and collimating light for long-distance illumination with minimized peripheral emission and glare. More particularly, it is a method of amplifying and condensing light into an annular ring by employing a principle similar to collimation of light in lasers.
Methods for directing light for long-distance illumination have included various forms of paraboloidal reflectors at one side or end of a light source and magnifying, shielding and peripheral filters for directing light beams from the opposite side or end of the light source. Notable have been U.S. Pat. No. 4,701,834 which teaches a paraboloidal configuration of a reflector with uniquely zoned sections for accomplishing reflection in desired directions while inhibiting reflection in undesired directions of illumination. This method does not concentrate or fully collimate all light in a desired direction. U.S. Pat. No. 4,731,713 teaches a separate parabolic reflector characteristic for upward reflection than for downward reflection of light. This method also leaves a great portion of the light quantum uncollimated into a single beam direction. U.S. Pat. No. 4,209,825 granted to Shackelford taught restriction of light to an elliptical form with an annular elliptical light orifice between covered inside and outside portions of a lens. The Shackelford patent employed an opaque and optically black center that could have been made to function as backing for a reverse reflecting light condenser if the effects had not been almost totally nullified by the outside opaque ring. The outside opaque ring inhibits condensed light precisely where it is most effective.
Some earlier prior art applied what could have been minor steps towards laser reflection, but apparently without sufficient understanding of the principle to employ it effectively. Included were U.S. Pat. Nos. 2,305,818, 2,199,014 and 2,147,543. These patents taught covering of an incandescent light at the center of a parabolic reflector with a light inhibitor with the intended effect of limiting direct glare from the light source independently. In these patents, glare was treated as a disadvantageous factor and eliminated rather than directed for greater effectiveness as taught by the instant invention. There were reverse reflectors but they were employed in methods that tended to decrease rather than to increase concentration of light in an annular ring. Reflection of all light to an outside ring of condensed light was not taught nor employed in the prior art.